He is 6-9 and considered athletic and was a 16th pick overall in the draft from Wake Forest. However he has been traded around to 3 different teams in the NBA (Bulls, Toronto and Sacramento) over the course of 4 years and has never had a breakout season.

Good ballhandling skills for a power forward... Nice shooter... Not a top-notch athlete... Pretty slow.

Despite being slow and nonathletic he can get up there and swat the rock averaging 1.4 bpg 2 years ago. Rotoworld.com fantasy news says, "Johnson was optimistic that a move to Sacramento last season would increase his role, but instead his playing time dwindled to 16 minutes per game in 54 appearances. He's a defensive specialist who may chip in a handful of steals and blocks if he makes one of the aforementioned teams".

My guess would be that he is probably slow in his decision making and not in his actual ability to move about the court. If what I just said is true, then a stable coaching and training environment could lead to his moves becoming automatic without having to take the time to think.